1. Field of the Invention
This invention relates to passive seatbelt systems in which the passenger is automatically caused to don the passenger seatbelt after entering the vehicle.
2. Prior Art
Although seatbelt systems are exceptionally effective in insuring the safety of passengers during vehicular emergencies, the percentage of passengers who wear seatbelts is extremely low because of the difficulty in donning the seatbelts, etc. As a result, various types of passive seatbelt systems have been proposed which make it possible to automatically fasten the passenger restraining seatbelt around the passenger after the passenger has entered the vehicle.
A typical system of this type is generally designed such that the outboard end of the seatbelt is anchored to the motor vehicle door and a motor installed inside the door is used to cause an intermediate portion of the seatbelt to move away from or approach the passenger seat in response to the opening or closing of the door. In passive seatbelt systems which use such a motor, however, costs are increased by the installation of the motor and a motor actuating sensor. Furthermore, the motor noise and the motor actuation timing also create problems and therefore the discomfort of the passenger is increased.
As a result, passive seatbelt systems have been proposed in which the opening and closing force of the door is used to cause an intermediate portion of the seatbelt to move away from or approach the passenger seat during opening or closing of the door so that there is no need for the driving force of a motor. In such passenger seatbelt system, however, the amount of space between the intermediate portion of the seatbelt and the passenger seat is proportional to the amount by which the door is opened or closed. Accordingly, such systems suffer from the drawback that when the door is not sufficiently opened, there is always insufficient space for the passenger to enter or leave the vehicle.